Reactor for gasifying coal under pressure

ABSTRACT

A reactor for the continuous gasification of coal under superatmospheric pressures and elevated temperatures with oxygen and water vapor and, if desired, additional gasifying agents is disclosed and includes a rotatable coal feeder disposed in the upper portion of the reactor having at least one feed chute. The longitudinal axis of the feed chute extends at an acute angle alpha to the vertical, which angle opens opposite to the direction of rotation of the feeder, and the leading edge of the outlet opening of the revolving feed chute is turned outwardly from a radial direction by an acute angle epsilon of from 5-20 degrees.

United States Patent Rudolph Sept. 2, 1975 [54] REACTOR FOR GASIFYINGCOAL UNDER 2,113,015 4/1938 Daniels 48/86 R PRESSURE 2,143,987 1/1939Koller 48/86 R 2,187,872 1/1940 Winkler 6t 211...... 48/202 X [75]Inventor: Paul R lph, B H m rg, 2,689,786 9 1954 Hubmann 48/77 x Germany[73] Assignee: Metallgesellschaft Aktiengesellschaft, Primary ExaminerSerwin Frankfurt am Main, Germany Attorney, Agent, or FzrmBurgess,Dlnklage & Sprung [22] Filed: Sept. 10, 1974 Appl. No.: 504,479

Foreign Application Priority Data Oct. 22, 1973 Germany 2352900References Cited UNITED STATES PATENTS 11/1920 Corthesy 48/73 X 7/1931Daae 48/86 R [5 7 ABSTRACT A reactor for the continuous gasification ofcoal under superatmospheric pressures and elevated temperatures withoxygen and water vapor and, if desired, additional gasifying agents isdisclosed and includes a rotatable coal feeder disposed in the upperportion of the reactor having at least one feed chute. The longitudinalaxis of the feed chute extends at an acute angle alpha to the vertical,which angle opens opposite to the direction of rotation of the feeder,and the leading edge of the outlet opening of the revolving feed chuteis turned outwardly from a radial direction by an acute angle epsilon offrom 5-20 degrees.

4 Claims, 3 Drawing Figures REACTOR FOR GASIFYING COAL UNDER PRESSUREBACKGROUND This invention relates to a reactor for a continuousgasification of coal under superatmospheric pressures and elevatedtemperatures by a treatment with oxygen and water vapor and, if desired,additional gasifying agents, comprising a rotatable coal feeder, whichis disposed in the upper portion of the reactor and comprises at leastone feed chute. v

Reactors of that kind consist usually of a cylindrical pressure vessel,which is suitably provided with a water jacket and contains in its lowerend a rotary grate, which cooperates with an ash discharge lock. Theconduits for feeding the gasify'ing agent may open in that rotary grate.A pressure lock is provided at the top end of the reactor and serves forfeeding the coal to be gasified. Means for withdrawing thetar-containing raw gas which is produced are also provided. Knownreactors have been described in the German Pat. No. 1,021,116 and theUS. Pat. No. 2,925,334.

In such continuously operating pressure reactors the coal in the densecoal bed descends toward the rotary grate while the coal isprogressively gasified and the ash content of the coal increasescontinuously. At the same time, new coal is continuously sprinkled fromthe feeder onto the fuel bed. It has been found in the operation ofknown reactors that the feeding of coal is not always satisfactory.Particularly in the gasification of caking coal the material to begasified swells so that the volume of coal or coke in the top portion ofthe gas producer is increased. As a result, the surface of the coal bedrises like the surface of a foaming liquid above the edge of the coaloutlet opening. Such rise and swelling of the uppermost portion of thecoal bed may easily cause a caking adjacent to the feed chute for thecoal. That caking may eventually result in a clogging of the outletopening of the chute for feeding the coal so that the operation of thegas producer is critically disturbed.

SUMMARY The invention avois the disadvantages of the prior art andensures that the coal is applied to the uppermost layer of the coal bedin a uniform and troublefree manner. This is accomplished according tothe invention in that the longitudinal axis of the feed chute extends atan acute angle a to the vertical, which angle opens opposite to thedirection of revolution, and that the leading edge of the outlet openingof the revolving feed chute is turned outwardly from a radial directionby an acute angle 6 of 20. As a result of this design of the feed chute,a component of motion which opposes the direction of rotation of thefeeder is imparted to the coal and bed coal which contacts the leadingedge of the outlet opening can readily flow radially outwardly alongsaid edge so that a build-up of coal is avoided.

The leading wall of the feed chute desirably rises at an angle 5 of 3060from the horizontal. In that case the coal is not plowed by the feedchute as is usual with known feeders. The leading wall now slides overthe surface of the coal bed and exerts a downward pressure thereon sothat the compaction of the swelling coal is promoted.

A further development of the invention resides in that the leading edgeof the outlet opening of the feed chute is disposed below the trailingedge thereof and the angle of rise 7 amounts to about 3l0 from thehorizontal. This feature additionally facilitates the flowing of coalfrom the feed chute and further reduces the likelihood of trouble. v

DESCRIPTION F THE DRAWING The inventionwill now be explained withreference to an example shown on the drawing, in which FIG. 1 is adiagrammatic longitudinal sectional view showing the upper portions of areactor for a pressure DESCRIPTION The gasification reactor comprises adoublewalled pressure vessel 1 and 2, which contains an internal waterjacket 3. The upper portion of the reactor contains a coal container,the walls of which are also watercooled. The coal in container 4 restson a rotatable distributor disc 5, which is secured to a hollow shaft 6,which is guided in bearings 7 and 8. A substantially cylindricaldisplacement body 9 is connected to the distributor disc 5 and projectsdownwardly and carries stirrer arms 10 and 11. A cooling water conduit12 extends in the hollow shaft 6 and serves to cool the displacementbody 9 and by means of branch conduits also the two stirrer arms 10 and11.

In operation, coal is fed from the supply in the container 4 through thedistributor disc 5 and its two feed chutes 13 and 14 continuously ontothe coal bed 15. The coal is gasified in the coal bed 15, and thegaseous reaction products are withdrawn through conduit 16 and suppliedto further use.

Reference is made to FIGS. 2 and 3 for an explanation of the design andarrangement of the feed chutes 13 and 14. During a rotation of the disc5, the chutes move in the direction of the arrow P and the coal flowsdownwardly onto the coal bed. The coal moves in the chutes 13 and 14approximately along their longitudinal axis A, which includes an acuteangle a (FIG. 3) with the vertical. The angle a may amount to about 822.The chute is inclined by this angle a in such a direction that acomponent of motion which opposes the rotary motion (arrow P) isimparted to the coal as it flows through the chute. This facilitates theflowing of coal onto the coal bed 15. This outflow is furtherfacilitated in that the trailing edge 17 is disposed above the leadingedge 18 so that the plane of the outlet opening 19 of the feed chutes 13and 14 is inclined from the horizontal plane by an angle a (FIG. 3)amounting to The leading wall 20 of each feed chute extends from theleading edge 18 of the chute and is upwardly inclined at an acute anglea (FIG. 3) which preferably amounts to 306O The provision of thisinclined leading wall 20 prevents a buildup of coal before the leadingwall during a rotation of the chutes 13 and 14 in the direction of thearrow P. Rather than plowing up the coal of the bed 15, the leading wall20 even exerts a certain downward pressure during the rotation of thefeeder. This design is particularly desirable for highly swelling coal.

It is apparent from FIG. 2 that the leading edge 18 of chutes 13 and 14includes an acute angle 6 (FIG. 2)

with the radial line R. The leading edge 18 is turned back outwardly,toward the housing wall 2, by that angle 6. As a result, that end of theleading edge 18 which adjoins the displacement body 9 leads the otherend so that a sliding guide is provided for the coal which contacts theleading edge 18 and the leading wall and said coal flows off outwardlyin the direction from the displacement body 9 toward the housing wall 2.This feature prevents the occurrence of a dead angle between thedisplacement body 9 and the chute 13 or 14 and an accumulation of coalin such dead angle.

What is claimed is:

l. Reactor for the continuous gasification of coal undersuperatmospheric pressures at elevated temperatures by treatment withoxygen and water vapor and, if desired, additional gasifying agents,comprising rotatable coal feeder means disposed in the upper portion ofthe reactor and having at least one feed chute means, the longitudinalaxis of said feed chute means extending at an acute angle alpha to thevertical, said angle opening opposite to the direction of rotation, theleading edge of the outlet opening of said feed chute means being turnedoutwardly from a radial direction by an acute angle epsilon of 520.

2. Reactor of claim 1 wherein the leading surface of the feed chuterises at an angle of 3060 from the horizontal.

3. Reactor of claim 1 wherein the leading edge of the outlet opening ofthe feed chute is disposed below the trailing edge thereof and the angleof rise alpha of about 3-l0 from the horizontal.

4. Reactor of claim 1 wherein the outlet opening adjoins the outside ofa displacement body extending downwardly below the outlet opening andhaving at least one radial stirrer arm disposed below the surface of thecoal bed during operation.

1. REACTOR FOR THE CONTINUOUS GASIFICATION OF COAL UNDERSUPERATMOSPHERIC PRESSURES AT ELEVATED TEMPERATURES BY TREATMENT WITHOXYGEN AND WATER VAPOR AND, IF DESIRED, ADDITIONAL GASIFYING, AGENTS,COMPRISING ROTATABLE COAL FEEDER MEANS DISPOSED IN THE UPPER PORTION OFTHE REACTOR AND HAVING AT LEAST ONE FEED CHUTE MEANS, THE LONGITUDINALAXIS OF SAID FEED CHUTE MEANS EXTENDING AT AN ACUTE ANGLE ALPHA TO THEVERTICAL, SAID ANGLE OPENING OPPOSITE TO THE DIRECTION OF ROTATION, THELEADING EDGE OF THE OUTLET OPENING OF SAID FEED CHUTE MEANS BEING TURNEDOUTWARDLY FROM A RADIAL DIRECTION BY AN ACUTE ANGLE EPSILON OF 5*-20*.2. Reactor of claim 1 wherein the leading surface of the feed chuterises at an angle of 30*-60* from the horizontal.
 3. Reactor of claim 1wherein the leading edge of the outlet opening of the feed chute isdisposed below the trailing edge thereof and the angle of rise alpha ofabout 3*-10* from the horizontal.
 4. Reactor of claim 1 wherein theoutlet opening adjoins the outside of a displacement body extendingdownwardly below the outlet opening and having at least one radialstirrer arm disposed below the surface of the coal bed during operation.